Has anyone ever had their RTT stolen? I can't recall ever hearing such a thing. You are right, most are bolted on with just a handful of bolts/nuts. I'm afraid any theft would not be a crime of opportunity, as it would take more than one person (typically) to remove the RTT. But leave it parked regularly in an unsecured area and all bets are off...
With the general ease to absconding with the entire truck, I'm more fearful of once again waking to an empty parking spot where I had left my truck the night before...
Locking nuts might deter the average Joe, but not someone intent on relieving you of your possession(s).
Come up with a rube goldberg style of mount (like mine) and now there are 16 bolts/nuts to deal with and then the RTT must be lifted vertically 3-4" to clear the rack. Even so, 15 well planned minutes of effort and *poof* it's gone with the wind - be simpler to relieve the truck of the bed rack and RTT in one fell swoop... though it'd require the concerted effort of 3-4 bodies.